Footwear is a fundamental piece of clothing that is worn in most communities throughout the world. Footwear protects the foot from extraneous trauma, it can provide comfort, and it is also a fashion item. It addition, certain footwear, for example, running shoes, are purported to provide improvements in performance and reductions in injury. Footwear can have a significant effect on the musculoskeletal system and there has been a substantial amount of research relating to these effects. One area of the musculoskeletal system that footwear has an effect on is muscle function. This chapter, therefore, concentrates on the effects of footwear on muscle function. To ensure a comprehensive and transparent review of the literature on this topic, and to minimize bias in the selection of information, we systematically searched the literature to incorporate all relevant studies.